A biometric system is basically a digital system made up of vulnerable components such as capture devices, communication channels and databases which are subjected to a wide spectrum of replay attempts and other forms of adversary attacks. Once the biometric sample is captured in the access control application, the digital biometric representation can be intercepted and misused to provide for illegitimate authentication.
It is possible to construct waveforms using additive techniques and to analyze and deconstruct waveforms as well. It is also possible to analyze the frequency partials of a recorded sound and then resynthesize a representation of the sound using a series of sinusoidal partials. By calculating the frequency and amplitude weighting of partials in the frequency domain (typically using a Fast Fourier transform), an additive resynthesis system can construct an equally weighted sinusoid at the same frequency for each partial. Older techniques rely on banks of filters to separate each sinusoid; their varying amplitudes are used as control functions for a new set of oscillators under the user's control. Because the sound is represented by a bank of oscillators inside the system, a user can make adjustments to the frequency and amplitude of any set of partials. The sound can be ‘reshaped’—by alterations made to timbre or the overall amplitude envelope, for example. A harmonic sound could be restructured to sound inharmonic, and vice versa.1 1http://en.wikibooks.org/wiki/Sound_Synthesis_Theory/Additive_Synthesis
Since biometric information describes a person, it is unlikely to be reset or reproduced should it be compromised unlike passwords or smartcards. Hence, the protection of the biometric data itself is of utmost importance, in order to allay anxiety among users over the privacy of their biometrics data. Acceptance of the system is also influenced by the security measures implemented on the biometric data.
Although single-modality biometric systems can achieve high performance in some cases, they are usually not robust except under ideal conditions and do not meet the needs of many potential voice recognition applications. These conditions can cause the system to be very inefficient and produce false positives that could compromise the security position of the system in which it is installed to protect.
There are many factors that can affect the quality and degradation of the audio such as environmental and extraneous audio from the environment where the system is installed. In one conventional system, the user usually speaks a key word or phrase into some type of microphone and that single audio clip is compared against one that has been stored for comparison and authentication. More complex systems include several multisampling processors involved to divide the input audio, slice it into smaller sections and compare those with better resolution. While this latter method is an improvement, it fails to provide the high level of accuracy often required in our times.
Recent advances in biometric technologies coupled with the increased threats in information security has proliferated the applications of biometric systems to safe-guard information and its supporting processes, systems and infrastructures. Physical and logical access controls are essentially based on user authentication whereby an individual's identity is verified through either one of the three following means:    by something he knows', ‘by something he has’ or ‘by something he is’ (or through combinations of any of the three means).
Traditional approaches are basically based on the first two methods. The former implies password authentication that can be forgotten, guessed or cracked through dictionary or brute forced attacks, whereas the latter involves the use of tokens as identifiers such as keys or smartcards for authentication purposes. Unfortunately, the second method is also at risk of being shared, lost, duplicated, or stolen. The emerging solution is based on biometric which is claimed to be more reliable and more fool-proof that relies on ‘something that you are’, to make personal authentication. For example, a voice recognition system which worked well with a quiet background, will not be as accurate in a real world environment. Thus becoming slow and ineffective as it must perform the security identification task multiple times in order to pass a positive or false positive response to the system.
There is therefore a need for a biometric identification method and system that addresses the above noted deficiencies of the conventional systems and methods.